Studies carried out in our lab as well as others have demonstrated the presence of the TAG-72 and CEA tumor associated antigens in a high percentage of human carcinomas. Our studies have focused on understanding the role of these molecules in tumorigenesis as well as understanding the molecular mechanisms involved in the regulation of expression of these antigens. Specific probes for members of the CEA gene family will be used to study their expression in various tissues and cell lines and to examine the mechanism of regulation of CEA expression by interferons as well as other biological response modifiers. In addition, the gene encoding CEA will be cloned and transfected into mouse metastatic cell lines in order to obtain a mouse model for the study of anti- tumor agents. Polyclonal antisera to deglycosylated TAG-72 and monoclonal antibodies to native TAG-72 will be used to obtain clones from cDNA libraries. Positive clones will be sequenced and used for analysis of TAG-72 expression in normal and tumor cell line and tissues.